Tag Archives: green catalysts

Canadian and Japanese researchers create new technique for using iron nanoparticles in greener hydrogenation process

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McGill University’s Audrey Moores and her team’s latest green chemistry work with researchers at RIKEN (The Institute of Physical and Chemical Research, Wako, Japan) and the Institute for Molecular Science (Okazaki, Japan) is featured in a June 27, 2013 news item on Nanowerk,

Researchers from McGill University, RIKEN (The Institute of Physical and Chemical Research, Wako, Japan) and the Institute for Molecular Science (Okazaki, Japan) have discovered a way to make the widely used chemical process of hydrogenation more environmentally friendly – and less expensive.

Hydrogenation is a chemical process used in a wide range of industrial applications, from food products, such as margarine, to petrochemicals and pharmaceuticals. The process typically involves the use of heavy metals, such as palladium or platinum, to catalyze the chemical reaction. While these metals are very efficient catalysts, they are also non-renewable, costly, and subject to sharp price fluctuations on international markets.

Because these metals are also toxic, even in small quantities, they also raise environmental and safety concerns. Pharmaceutical companies, for example, must use expensive purification methods to limit residual levels of these elements in pharmaceutical products. Iron, by contrast, is both naturally abundant and far less toxic than heavy metals.

Previous work by other researchers has shown that iron nanoparticles — tiny pieces of metallic iron — can be used to activate the hydrogenation reaction. Iron, however, has a well-known drawback: it rusts in the presence of oxygen or water. When rusted, iron nanoparticles stop acting as hydrogenation catalysts. This problem, which occurs with so much as trace quantities of water, has prevented iron nanoparticles from being used in industry.

The June 27, 2013 McGill University news release on EurekAlert, which originated the news item, provides details about the new technique,

The key to this new method is to produce the particles directly inside a polymer matrix, composed of amphiphilic polymers based on polystyrene and polyethylene glycol. The polymer acts as a wrapping film that protects the iron surface from rusting in the presence of water, while allowing the reactants to reach the water and react.

This innovation enabled the researchers to use iron nanoparticles as catalyst in a flow system, raising the possibility that iron could be used to replace platinum-series metals for hydrogenation under industrial conditions.

“Our research is now focused on achieving a better understanding of how the polymers are protecting the surface of the iron from water, while at the same time allowing the iron to interact with the substrate,” says Audrey Moores, an assistant professor of chemistry at McGill and co-corresponding author of the paper.

…

“The approach we have developed through this collaboration could lead to more sustainable industrial processes,” says Prof. Uozumi [Prof. Yasuhiro Uozumi of Riken]. “This technique provides a system in which the reaction can happen over and over with the same small amount of a catalytic material, and it enables it to take place in almost pure water — the green solvent par excellence.”

I last wrote about greener chemistry and iron nanoparticles in a March 28, 2012 posting concerning some work at the University of Toronto while the last time McGill, green chemistry, and Audrey Moores were mentioned here was in a Jan. 10, 2011 posting concerning ‘nanomagnetics.

For those who are interested in this latest work from McGill, here’s a link to and a citation for the published paper,

Highly efficient iron(0) nanoparticle-catalyzed hydrogenation in water in flow by Reuben Hudson, Go Hamasaka, Takao Osako, Yoichi M. A. Yamada, Chao-Jun Li, Yasuhiro Uozumi, and Audrey Moores.
Green Chem., 2013, Advance Article DOI: 10.1039/C3GC40789F

First published online 27 Jun 2013

This paper is behind a paywall.

Greener catalysts with iron nanoparticles

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A research team at the University of Toronto has announced the discovery of a possible ‘green’ alternative to commonly used catalysts in the food, drug, and fragrance industries. From the March 27, 2012 news item on Nanowerk,

A chemistry team at the University of Toronto has discovered environmentally-friendly iron-based nanoparticle catalysts that work as well as the expensive, toxic, metal-based catalysts that are currently in wide use by the drug, fragrance and food industry.

“It is always important to strive to make industrial syntheses more green, and using iron catalysts is not only much less toxic, but it is also much more cost effective,” said Jessica Sonnenberg, a PhD student and lead author of a paper published this week in the Journal of the American Chemical Society (“Iron Nanoparticles Catalyzing the Asymmetric Transfer Hydrogenation of Ketones”).

The March 27, 2012 University of Toronto news release provides a quote from Sonnenberg which suggests there’s still a lot more work to be done before the toxic metal-based catalysts currently being used could be replaced,

… “Catalysts, even cheap iron ones developed for these types of reaction, still suffer one major downfall,” explained Sonnenberg.  “They require a one-to-one ratio of very expensive organic ligands – the molecule that binds to the central metal atom of a chemical compound – to yield catalytic activity. Our discovery of functional surface nanoparticles opens the door to using much smaller ratios of these expensive compounds relative to the metal centres.  This drastically reduces the overall cost of the transformations.”

This work at the University of Toronto reminded me of another team also working on green catalysts for chemical reactions and also based in Canada, this time at McGill University. The McGill team lead by Chao-Jun Li was mentioned most recently here in a Jan. 10, 2011 posting where their ‘nanomagnetics’ technology to replace the current toxic catalysts  is described.